we're talking about stephen hawking. he asks do aliens exist? and also has made headlines that now, he's changed his mind. that we don't need god to explain the universe. >> wow. highly-controversial. but he is brilliant, as you said, george. >>> and can brain surgery stop obesity? we'll show you a radical, new treatment that one woman has undergone to control her food obsession through her brain. >> martin bashir investigated that for "nightline." we'll talk to him in a minute. >>> first of all, i'm going to take a stroll down here. one of the waciest show wackie have on tv. that's "wipe-out." jill wagner, ladies and gentlemen. a huge fan. huge fan. you all have seen "wipe-out." the obstacle course? >> how many want to be on the show? yeah. >> they're vying for -- have you seen what they do to contestants on the show? jill, you're right there, up close and personal. i'm wincing at home. what's it like being there? >> i can't tell you. i feel like a big kid every day. it's fun. we want you to come on the show, robin. >> i don't want to get my ha